/*从浏览器打开*/
#mcover {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.7);
    display: none;
    z-index: 20000;
}
#mcover img {
    position: fixed;
    right: 25px;
    top: 5px;
    width: 260px;
    height: 160px;
    z-index: 999;
}